Sewing machine looper mechanism



1959 c. w. JQOHNSON 2,900,939

SEWING MACHINE LOOPER MECHANISM Filed May 7, 1956 3 Sheets-Sheet 1 FIG.

56 INVENTOR CARL W. JOHNSON /02 ATTORNEY g- 1959 c. w. JOHNSON 2,900,939

SEWING MACHINE LQOPER MECHANISM Filed May 7, 195a s Sheets-Sheet 2 INVENTOR CARL W. JOHNSON WZW ATTO R N EY g- 25, 1959 c. w. JOHNSON v 2,900,939

SEWING MACHINE LOOPER macnmxsm 3 Sheets-Sheet 5 Filed May 7, 1956 FIG. 5 /32 M m8 m m0 WJ W BY ATTOR EY United States Patent 9 SEWING MACHINE LOOPER MECHANISM Carl W. Johnson, Brooklyn, N.Y., assiguor to American Machine & Foundry Company, a corporation of New Jersey Application May 7, 1956, Serial No. 583,027

8 Claims. (Cl. 112 171) The invention relates to sewing machines and more particularly to short thread sewing machines which utilize a double pointed needle having an eye located between the points, and wherein the opposite ends of the needle are grasped alternately by the jaws of opposed needle bars in order to move the needle and thread back and forth through the work in forming stitches.

A machine of the type described above has many uses in the manufacture of articles of clothing such as gloves, mens and womens apparel and novelty collars. In stitching certain types of articles, such for example as collars of mens shirts, it is desirable that the short thread used in the machine be of such a length that the entire collar can be stitched without the necessity of piecing the thread. Otherwise, if it is necessary to piece the thread, which heretofore has required the use of a second thread to continue the formation of stitches, the piecing may show and an unsatisfactory finished product result.

The present invention makes it unnecessary to rethread the needle during the stitching of certain articles, such for example as collars of mens shirts. With the mechanism embodying the invention, a much greater length of thread can be used than was possible in machines available heretofore. The invention therefore results in the production of more satisfactory products and a substantial reduction in time formerly required for rethreading of needles, and stopping and starting of stitching operations because of the need for replacing and piecing the thread.

The invention is characterized by the provision of a sewing machine provided with a novel thread pulling mechanism or looper which pulls the loose end of a short thread through the work with great rapidity, thereby making it possible to use a thread of substantially increased length than heretofore was possible in the art.

It is an object of the invention to provide a novel thread pulling or looper mechanism for use in a short thread sewing machine wherein the construction and operation of the mechanism is such that it is possible to use a much longer thread and thereby improve the appearance of the work and decrease costs because of the substantial reduction in time required to rethread the needle and restart the operation of the machine subsequent to the rethreading.

It is also an object of the invention to provide a novel thread handling mechanism including a two revolution thread puller or looper operative to so handle a length of thread that a substantially increased length of thread can be used in the machine.

It is a further object of the invention to provide a novel thread looper or thread pulling mechanism for use with a short thread sewing machine wherein a double crank motion is operative to control the movement of the thread looper or puller in its engagement with a loop of thread and the subsequent pulling thereof through the work so that a substantially longer length of thread can be used than was heretofore possible in the art.

With these and other objects not specifically mentioned in view, the invention consists in certain combinations and ice constructions which will be hereinafter fully described, and then set forth in the claims hereunto appended.

In the accompanying drawings which form a part of this specification, and in which like characters of reference indicate the same or like parts:

Fig. 1 is a sectional side elevation of an under and over stitch sewing machine provided with a preferred form of looper operating mechanism embodying the invention.

Fig. 2 is a partial front elevation of the mechanism shown in Fig. 1.

Fig. 3 is a side elevation of a modified form of looper operating mechanism.

Fig. 4 is a sectional front elevation taken on line 4-4 of Fig. 3.

Fig. 5 is a side elevation taken on line 55 of Fig. 4.

Fig. 6 is a sectional end elevation taken on line 6--6 of Fig. 3.

Referring to the drawings, there is disclosed apparatus constructed in accordance with the invention, and embodied in a sewing machine which may be similar in construction and operation to that illustrated and described in Johnson Patent 2,386,800, granted October 16, 1945.

The sewing machine is driven through a belt 10 running on pulley 12 secured to hub 14 of gear 16 rotatably supported on a headed stud 18 attached by suitable screws 22 to the machine frame 20. Belt 10 is driven by a pulley (not shown) which is integral with a suitable clutch mechanism (not shown) driven from a motor (not shown) in a manner similar to that disclosed in Patent No. 2,368,066 issued to C. W. Johnson January 23, 1945. Since the drive, as well as the mechanism for operating the clutch and brake form no part of the present invention, further showing and description thereof are omitted.

A cam 24 preferably formed integrally with pulley 12 is provided with a cam track 26 in which run cam rollers 28 and 30 positioned at diametrically opposite points of cam 24. Cam roller 28 is pivotally attached to a cam lever 32 projecting from the rear end of an elongated hub or sleeve 34 pivotally mounted on horizontal shaft 36 held at one end by a suitable bearing bracket 38 and at the other end by another suitable bearing lug 40. Cam roller 30 is pivotally attached to a cam lever 42 which projects rearwardly from an end of an elongated hub or sleeve 44 loosely supported on a suitably mounted horizontal shaft 46.

The machine is provided with an upper needle bar 48 and a lower needle bar 50, both vertically positioned and arranged in axial alignment. Each needle bar carries an actuating member 52 and 54, respectively. Actuating member 52 of the upper needle bar 48 engages with a shoe or roller 56 pivotally mounted on an actuating arm 58 projecting from the forward end of sleeve 34. Actuating member 54 of the lower needle bar 50 engages with a roller 60 pivotally attached to the free end of an actuating arm 62 projecting from the forward end of sleeve 44. Since the actuating members 52 and 54 of the upper and lower needle bars, respectively, are of the sliding block type, oscillating motion imparted to actuating arms 58 and 62 and sleeve members 34 and 44 by cam 24 through cam levers 32 and 42, respectively, is converted into vertical reciprocating motion of needle bars 48 and 50 which are guided in suitable bushings in guide lugs 64 and 66, respectively.

Needle N, which is moved back and forth through the work by needle bars 48 and 50, is provided with a point at each end and an eye through which the thread passes, located preferably about midway therebetween. Since both needle bars 48 and 50 are constructed in the same manner as the needle bars shown and described in Patent 2,386,800, a detailed description thereof is deemed unnecessary and is omitted in the present case. It will be understood by those skilled in the art that in this type of machine, needle N is grasped alternately by the jaws of each needle bar as the needle is pushed vertically downward or upward through the work or material M (Fig. 2)

, The machine is also provided with a thread pulling device designated generally 68 comprising an arm 70 which on its upper free end carries a thread engaging head 72 so mounted that it may rotate around the periphery of a stationary thread drum 74 which is suitably secured to a frame portion of the machine. The chief function of the thread puller is to engage with its head 72 the loop L of the thread on alternate movements of the needle N and pull the loose end of the thread through the work or material over upper looper 75 movably mounted above the work supporting table T (Fig. 2), and dispose it about the periphery of the drum 74 in such a manner that the danger of snarling, fouling or breaking the thread is practically eliminated. Thread puller head 72, upper looper 75, the work feeding means (not shown), and drum 74 are similar in construction and operation to those shown in Johnson Patent 2,368,066, and since they form n'o specific part of the invention, further detailed showing and description thereof are omitted.

Since the loose end of the thread has to be pulled through the work and deposited upon drum 74 before the needle N can be pushed upwardly again through the work by the lower needle bar, the length of the thread that can be used is determined by the speed with which the above mentioned loose end can be pulled through the work by the thread puller.

Figs. 1 and 2 disclose a stitching machine provided with one form of novel thread puller or looper 68 and operating mechanism therefor. Thread puller 68 is revolved about drum 74 twice during one cycle of the machine, instead of only once, as in the machine disclosed in the above referred to Johnson patents. Due to the number of revolutions of thread puller 68, a substantially longer length of thread can be used because of the novel manner in which the loose end is pulled through the work and disposed on drum 74 out of the path of travel of needle N.

In order to avoid interference with the upward moving lower needle bar 50 as thread puller 68 passes the latter during its second revolution, means are provided to move thread puller 68 laterally during a portion of its revolving movement to prevent such undesirable interference.

Thread puller arm 70, shown in Figs. 1 and 2, is mounted on one end of a horizontal shaft 76, to the other end of which is secured a gear 78. Shaft 76 also carries a sleeve member 80 loosely mounted thereon and extending from the face of the hub of arm 70 to the face of the hub of gear 78 (Fig. l). Sleeve member 80 in turn is slidingly supported by a suitable bearing bracket 82 secured to a frame portion of the machine. The comparatively narrow gear 78, which is mounted on and rotates shaft 76, meshes with a wide gear 84 loosely mounted on horizontal stud shaft 86 mounted on a suitable frame portion of the machine. Gear 84 also meshes with and is driven by gear 88 loosely mounted on stud shaft 90 mounted on a suitable frame portion of the machine. Gear 88 preferably is integral with a gear 92 and 94, the latter of which through a suitable gear train 96, is connected with and driven by gear 16 mentioned heretofore. By means of the gear arrangement illustrated, gear 78 and shaft 76 are rotated two revolutions for each single revolution of gear 88.

The lateral displacement of arm 70 for the purposes described, is accomplished by means of a cam lever 98. The upper free end of lever 98 is pivotally attached to one end of sleeve member 80 while the lower end of cam lever 98 is loosely supported on stud 100 held by bracket 102 attached to a frame portion of the machine. Cam lever 98 carries a cam roller 104 which runs in a track 105 in a suitable cam 106 formed integrally with the hub of gear 84 which, as mentioned above, drives gear 78 on the shaft 76 which carries thread puller arm 70. It will be seen that every time cam roller 104 runs on the high portion 107 of cam track 105, cam lever 98 moves the sleeve member in a horizontal direction to the left, as viewed in Fig. 1, which in turn also effects a lateral displacement of the shaft 76 and consequently a movement of the thread puller arm 70 away from needle bar 50. For better dynamic balance, the arm 70 is provided with a counterbalance arm 108.

Figs. 3, 4, 5 and 6 illustrate a modified form of the thread pulling device or looper which is actuated by a double crank system. The construction and operation of this system described hereinbelow are such that the thread puller, after it is moved into engagement with a loop L formed in the thread on the upward movement of needle N and substantially simultaneously with its engagement with the loop, is moved rapidly through approximately 180 to pull the loose end of the thread through the work at such speed that it permits the use of a substantially longer thread than heretofore possible in existing machines of the short thread type.

As shown in Figs. 3, 4, 5 and 6, thread puller arm 70 is secured to a horizontal shaft rotatably supported in a suitable bearing bracket 122 attached to a frame portion of the machine. To shaft 120 is also secured an actuating arm 124 which through an H-shaped link 126, is connected to a pivot 128 carried by the free end of lever 130, the other end of which is pivotally connected to a stud 132 carried by the forked free end of crank arm 134 loosely mounted on shaft 120. A cam follower 136 mounted substantially at the center portion of lever engages with an eccentric cam track 138 of a stationary cam 140 secured to the frame of the machine. A cam roller 142 pivotally attached to stud 132 on the free end of crank arm 134 engages a track 144 formed by a pair of bars 146 secured to gear 92 which is the same construction and design as that shown in Figs. 1 and 2, and is integral with gear 94 driven in turn through the gear train 96 from the main drive gear 16 of the machine.

As the mechanism mounted on shaft 120 rotates about the stationary eccentric cam 140, the double crank arrangement imparts an auxiliary motion to thread puller arm 70, speeding it up during one half of the cycle and slowing it down during the other half. This extra speedup enables thread puller 68 to engage the loop of thread slowly when it is adjacent needle N when it is held in lower bar 50 and then speed up and travel at a high rate of speed in moving to a point therefrom. This operation makes it possible to pull a longer thread through the work so that the loose end of the thread is cleared before the needle starts back up through the material.

In a short stitch sewing machine provided with thread pullers or loopers construction in accordance with the invention, it is possible to use a thread having a length up to twenty percent (20%) greater than has been possible heretofore in the art. I-twill be seen, therefore, that the invention contributes not only to improved appearance in goods stitched on a machine provided with the invention, but also the machine can be operated for longer periods of time without rethreading.

What I claim is:

1. In a sewing machine, the combination with a needle and opposed upper and lower needle bars, of means for alternately connecting said needle with said bars and projecting said needle with a thread having a fixed end and a loose end through work to be stitched, a drum located adjacent said lower needle bar, a thread puller device cooperating with said drum to pull the loose end of said thread through the work and lay it on said drum, driving means for operating said needle bars in a predetermined normal cyclical rate of speed, and mechanism for driving said shaft for moving said thread puller relative to said drum for at least a part of its travel along said drum at a speed greater than said normal cyclical operation of said driving means, whereby said loose end of said thread is pulled rapidly through said work and disposed on said drum, said mechanism including a shaft mounting said thread puller for rotary movement, an actuating arm attached to said shaft, a link having one end connected to said actuating arm, a second link having one end connected to the other end of said first-named link, a crank arm loosely mounted on said shaft, with the free end of said crank arm connected to the other end of said second-named link, a cam follower mounted on said second-named link, a cam having a track engaged by said cam follower, and means for driving said crank arm, whereby in response to the operation of said mechanism said thread puller is moved slowly to a point of engagement with a loop of thread adjacent said lower needle bar and then moved with a highly accelerated movement to a point substantially 180 from said point of engagement with said loop to rapidly pull a relatively long length of thread through said work.

2. In a sewing machine, the combination with a needle and opposed upper and lower needle bars, of means for alternately connecting said needle with said bars and projecting said needle with a thread having a fixed end and a loose end through work to be stitched, a drum located adjacent said lower needle bar, a thread puller device cooperating with said drum to pull the loose end of said thread through the work and lay it on said drum, driving means for operating said needle bars in a predetermined normal cyclical rate of speed, and mechanism for driving said shaft for moving said thread puller relative to said drum for at least a part of its travel along said drum at a speed greater than said normal cyclical operation of said driving means, whereby said loose end of said thread is pulled rapidly through said work and disposed on said drum, saidv mechanism including a shaft mounting said thread puller for rotary movement, an actuating arm attached to said shaft, a crank arm loosely mounted on said shaft, means connecting said actuating arm to said crank arm, a cam follower on said crank arm, driving means for said crank arm, and cam means mounted on said last-named means, whereby in response to the operation of said mechanism said thread puller is moved slowly into engagement with a loop of thread and then accelerated to rapidly pull a relatively long length of thread through said work.

3. The invention as described in claim 2 wherein said means connecting said actuating arm to said crank arm includes a link having one end connected to said actuating arm, and a second link having one end connected to the other end of said first-named link and the other end of said second-named link connected to the free end of said crank arm.

4. In a sewing machine, the combination with a needle and opposed upper and lower needle bars, of means for alternately connecting said needle with said bars and projecting said needle with a thread having a fixed end and a loose end through work to be stitched, a drum located adjacent said lower needle bar, a thread puller device cooperating with said drum to pull the loose end of said thread through the work and lay it on said drum, driving means for operating said needle bars in a predetermined normal cyclical rate of speed, and mechanism for driving said shaft for moving said thread puller relative to said drum for at least a part of its travel along said drum at a speed greater than said normal cyclical operation of said driving means, whereby said loose end of said thread is pulled rapidly through said work and disposed on said drum, said mechanism including a shaft mounting said thread puller for rotary movement, an actuating arm attached to said shaft, a link having one end connected to said actuating arm, a second link having one end connected to the other end of said first-named link, a crank arm loosely mounted on said shaft, with the free end of said crank arrn connected to the other end of said second-named link, a cam follower mounted on said second-named link, a cam having a track en- 6 gaged by said cam follower, a cam roller pivotally mounted on said second-named link, a second cam track engaged by said cam roller, and means for driving said crank arm, whereby in response to the operation of said mechanism said thread puller is moved slowly to a point of engagement with a loop of thread adjacent said lower needle bar and then moved with a highly accelerated movement to a point remote from said point of engagement with said loop to rapidly pull a relatively long length of thread through said work.

5. In a sewing machine, the combination with a needle and opposed upper and lower needle bars, of means for alternately connecting said needle with said bars and projecting said needle with a thread having a fixed end and a loose end through work to be stitched, a drum located adjacent said lower needle bar, a thread puller device cooperating with said drum to pull the loose end of said thread through the work and lay it on said drum, driving means for operating said needle bars in a predetermined normal cyclical rate of speed, and mechanism for driving said shaft for moving said thread puller relative to said drum for at least a part of its travel along said drum at a speed greater than said normal cyclical operation of said driving means, whereby said loose end of said thread is pulled rapidly through said work and disposed on said drum, said mechanism including a shaft mounting said thread puller for rotary movement, an actuating arm attached to said shaft, a link having one end connected to said actuating arm, a second link having one end connected to the other end of said first-named link, a crank arm loosely mounted on said shaft, with the free end of said crank arm connected to the other end of said secondnamed link, means for driving said crank arm, a cam follower mounted adjacent the middle of said secondnamed link, a cam having a track engaged by said cam follower, a cam roller loosely mounted on the end of said second-named link adjacent said crank arm, and spaced guide bars forming a linear cam track for said cam roller whereby in response to the operation of said mechanism said thread puller is moved slowly to a point of engagement with a loop of thread adjacent said lower needle bar and then moved with a highly accelerated movement to a point substantially opposite from said point of engagement with said loop to rapidly pull a relatively long length of thread through said work.

6. In a sewing machine, a Work support table, needle operating mechanism for passing a double pointed needle having an eye located between its points back and forth through work moved over said support table, means for supporting a portion of a length of thread having a loose end and threaded through the eye of said needle above said work, a thread support surface, a thread puller for engaging loops formed in said thread below said work and for pulling the loose end of said thread through said work and laying it on said support table, a shaft supporting said thread puller, means for operating said needle operating mechanism and means for rotating said shaft for moving said thread puller relative to said support table for at least a part of its travel at a speed greater than said normal cyclical operation of said needle operating mechanism, whereby said loose end of said thread is pulled rapidly through said work and disposed on said support table, said last-named means including a shaft mounting said thread puller for rotary movement, an actuating arm attached to said shaft, a crank arm loosely mounted on said shaft, link means connecting said actuating arm to said crank arm, driving means for said crank arm, cam means mounted on said driving means, and means for actuating said driving means whereby in response to the operation of said shaft rotating means, said thread puller is moved slowly to a point of engagement with a loop of thread and then moved with a highly accelerated movement to point remote from said point of engagement with said loop to rapidly pull a relatively long length of thread through said work.

7. In a sewing machine, a work support table, needle operating mechanism for passing a double pointed needle having an eye located between its points back and forth through work moved over said support table, means for supporting a portion of a length of thread having a loose end and threaded through the eye of said needle above said work, a thread support surface, a thread puller for engaging loops formed in said thread below said work and for pulling the loose end of said thread through said work and laying it on said support table, a shaft supporting said thread puller, means for operating said needle operating mechanism and means for rotating said shaft for moving said thread puller relative to said support table for at least a part of its travel at a speed greater than said normal cyclical operation of said needle operating mechanism, whereby said loose end of said thread is pulled rapidly through said work and disposed on said support table, said last-named means including a shaft mounting said thread puller for rotary movement, an actuating arm attached to said shaft, a link having one end connected to said actuating arm, a second link having one end connected to the other end of said first-named link, a crank arm loosely mounted on said shaft, with the free end of said crank arm connected to the other end of said secondnamed link, a cam follower mounted on said secondnamed link, a cam having a track engaged by said cam follower, and means for driving said crank arm, whereby in response to the operation of said shaft rotating means said thread puller is moved slowly to a point of engagement with a loop of thread and then moved with a highly accelerated movement to a point substantially opposite said point of engagement with said loop to rapidly pull a relatively long length of thread through said work.

8. In a sewing machine, a work support table, needle operating mechanism for passing a double pointed needle having an eye located between its points back and forth through work moved over said support table, means for supporting a portion of a length of thread having a loose end and threaded through the eye of said needle above said work, a thread support surface, a thread puller for engaging loops formed in said thread below said work and for pulling the loose end of said thread through said work and laying it on said support table, a shaft supporting said thread puller, means for operating said needle operating mechanism and means for rotating said shaft for moving said thread puller relative to said support table for at least a part of its travel at a speed greater than said normal cyclical operation of said needle operating mechanism, whereby said loose end of said thread is pulled rapidly through said work and disposed on said support table, said last-named means including a shaft mounting said thread puller for rotary movement, an actuating arm attached to said shaft, a link having one end connected to said actuating arm, a second link having one end connected to the otherend of said first-named link, a crank arm loosely mounted on said shaft, with the free end of said crank arm connected to the other end of said second-named link, a cam follower mounted on said second-named link, a cam having a track engaged by said cam follower, a cam roller pivotally mounted on said second-named link, a second cam track engaged by said cam roller, and means for driving said crank arm, whereby in response to the operation ofsaid shaft rotating means said thread puller is moved slowly to a point of engagement with a loop of thread and then moved with a highly accelerated movement to a point substantially opposite said point of engagement with said loop to rapidly pull a relatively long length of thread through said work.

References Cited in the file of this patent I UNITED STATES PATENTS 2,386,800 Johnson Oct. 16, 1945 2,523,054 Pederson Sept. 19, 1950 2,655,817 Armelin Oct. 20, 1953 

